High-frequency iron-cored coil



March 1951 E. A. VAN YZEREN 2,544,195

HIGH-FREQUENCY men-com cqn.

Filed April 22,' 1946 IN VEN TOR.

EWOUD A. VAN YZEREN ATTORNEY Patented Mar. 6, 1951 HIGH-FREQUENCY IRON-CORE!) COIL Eweud Adriaan van Yaeren, Eindhoven, Netherlands. asaignor, by meane assignments, to Hartiord National Bank and Trust Company. Hartiord. Conn, as trustee Application April 22, 1946, Serial No. 663,824 In the Netherianb, August 27, 1942 Section 1, Public Law 090, August 8, 1946 Patent expires August 2'1, 1962 1 Claim. 1

This invention relates to a high-irequency iron-cored coil. consisting of a core oi high frequency iron with a winding provided thereon and a shell also consisting oi high-frequency iron which completely surrounds the core and the winding, air gaps between core and shell being avoided.

Such high-frequency coils, which are called iron-clad cored coils, are used in radio receiving sets as inductance coils oi resonant circuits which are tunable by means oi a variable condenser. In mass-production oi these coils small deviations irom the desired inductance value always occur which require final adjustment to the desired value. In a well-known construction oi iron-clad cored coils this adjustment is possible since the shell consists oi two parts one oi which is rigidly connected to the core and the other is shaped as a ring which is movable on the core and within the first-mentioned part oi the shell.

The displacement oi the ring involves a variation oi the inductance due to variation oi the magnetic resistance oi the magnetic circuit. This variation of the magnetic resistance exclusively results irom an increase or a decrease in length oi the path oi the lines oi iorce. This involves the drawback that the adjustment oi the inductance is always accompanied by a variation oi the losses since, ior instance, an increase oi the path oi the lines or iorce will bring about an increase oi the iron volume which, as is well-known, increases the losses. The invention has ior its purpose to provide a construction which permits adjustment oi the inductance oi iron-clad cored coils without modiiying the iron volume, so that the losses oi the coil are not appreciably aiiected by adjustment oi the inductance.

According to the invention this is achieved y iorming the shell oi two parts in such manner core i made from high-frequency iron. The shell consists of two cylindrical parts i and 3 which also consist of high-irequency iron and both of which are movable on the core I. The winding provided on the core I is designated by 4. By shifting the two shells parts 2 and 3 relatively to one another the air-gap I formed between them can be adjusted and consequently also the inductance oi the coil. Since a slight variation of the air-gap involves a considerable variation of the magnetic resistance of the circuit and the deviation of the inductance from the desired value is small as a rule, only Slight variations oi the air-gap are necessary for adjusting the inductance to the desired value, so that the adjustment does not entail an appreciable variation of the iron volume. As a result thereof the losses also remain practically unchanged.

The form of construction represented in Fig. 2 solely differs from that shown in Fig. 1 in that only one part of the shell, viz. the part 3, is movable on the core I. The other part 2 constitutes a mechanical unit with the core I.

What I claim is:

18 A high irequency inductance coil comprising a that at least one oi two parts is movable over'the 40 core and an adjustable air-gap is iormed between the two parts oi the shell. variable air-laps between core and shell being avoided.

The drawing represents two icrms oi construction oi a high-irequency coil according to the 2,130,815

invention.

l 'lg.irepresentlacoiihavingacyiindrical cylindrical core of high-frequency iron, a coil winding disposed on said core, and a cylindrical high frequency iron shell encasing said core and said coil comprising two congruent cylindrical portions, one of said shell portions being movable relative to said core and provided with an apertured portion ior passing said core therethrough. said core and said movable shell portion interiltting with a constant air-gap.

EWOUD ADRIAAN VAlI- YZEREN.

REFERENCES CITED The iollowing reierences are of record in fire ille oi this patent:

UNITED STATES PATENTS Number Name Date 1,925,224 Alder Sept. 5. 1933 2,064,772 Vogt Dec. 15. 1930 Riepka Sept. 20. 1938 2,180,850 Reiser Nov. 21. 1989 2,220,126 luv. 8. I

Bisetal. 

